HARMONIC FILTERS Design for IEC compliance

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1 HARMONIC FILTERS Design for IEC compliance Marius Jansen February 2011 GRID Overview What is a filter Types of harmonic filters What is harmonic compliance Designing for compliance Designing for reliability Other considerations 24/2/2011 / MJ - P 2 1

2 Filter defined Device or combination of devices Intended to reduce harmonic voltage distortion Caused by non-linear loads in the network That may be otherwise result in costs, losses or damage to other equipment in the network 24/2/2011 / MJ - P 3 Filter defined Device or combination of devices Can be a single filter, or a combination of several Can be located at a single node or be distributed Can be active or passive Can be part of equipment selection (transformer impedance or vector arrangement) Intended to reduce harmonic voltage distortion Caused by non-linear loads in the network That may be otherwise result in costs, losses or damage to other equipment in the network 24/2/2011 / MJ - P 4 2

3 Filter defined Device or combination of devices Intended to reduce harmonic voltage distortion Australian power quality focuses on voltage distortion Voltage distortion in the network is seen by all connected loads Caused by non-linear loads in the network That may be otherwise result in costs, losses or damage to other equipment in the network 24/2/2011 / MJ - P 5 Filter defined Passive filter presents a lower impedance path for harmonic current than the rest of the system The amount of harmonic absorption is a function of the filter configuration and the network impedance Filter impedance can be designed to reduce network voltage distortion 24/2/2011 / MJ - P 6 3

4 Filter defined Network impedance generally has multiple poles and zeroes 1000 DIgSILENT [-] T_BP: Network Impedance, Magnitude in Ohm Zsweep Date: 9/7/2010 Annex: /2 24/2/2011 / MJ - P 7 Overview What is a filter Types of harmonic filters What is harmonic compliance Designing for compliance Designing for reliability Other considerations 24/2/2011 / MJ - P 8 4

5 Types of harmonic filter Single tuned C-type Damped single tuned Double (and more) tuned 24/2/2011 / MJ - P 9 Types of harmonic filter Single tuned DIgSILENT [-] T-ST: Network Impedance, Magnitude in Ohm Zsweep(1) Date: 9/6/2010 Annex: /3 24/2/2011 / MJ - P 10 5

6 Types of harmonic filter Single tuned 24/2/2011 / MJ - P 11 Types of harmonic filter Damped single tuned DIgSILENT [-] T_BP: Network Impedance, Magnitude in Ohm Zsweep(1) Date: 9/6/2010 Annex: /3 24/2/2011 / MJ - P 12 6

7 Types of harmonic filter Damped single tuned 24/2/2011 / MJ - P 13 Types of harmonic filter C-type DIgSILENT [-] T_CT: Network Impedance, Magnitude in Ohm Zsweep(1) Date: 9/6/2010 Annex: /3 24/2/2011 / MJ - P 14 7

8 Types of harmonic filter C-type 24/2/2011 / MJ - P 15 Types of harmonic filter Double tuned DIgSILENT [-] T_DT: Network Impedance, Magnitude in Ohm Zsweep(1) Date: 9/6/2010 Annex: /3 24/2/2011 / MJ - P 16 8

9 Types of harmonic filter Double tuned 24/2/2011 / MJ - P 17 Types of harmonic filter Comparison Best Worst 24/2/2011 / MJ - P 18 9

10 Overview What is a filter Types of harmonic filters What is harmonic compliance Designing for compliance Designing for reliability Other considerations 24/2/2011 / MJ - P 19 Harmonic compliance AS/NZS /2/2011 / MJ - P 20 10

11 Harmonic compliance The table is the beginning, not the end of the story Network owners must set their own planning limits Emission limits must then be calculated according to the procedures in the standard for every new load to ensure planning levels are not exceeded These emission limits are the compliance limits They are always lower than the planning limits Emission limits are generally stated as voltage distortion at a busbar in the absence of other loads or background distortion 24/2/2011 / MJ - P 21 Harmonic compliance Typical emissions limit table: 24/2/2011 / MJ - P 22 11

12 Overview What is a filter Types of harmonic filters What is harmonic compliance Designing for compliance Designing for reliability Other considerations 24/2/2011 / MJ - P 23 Design for harmonic compliance Similar approach for compliance and reliability Compliance looks at the network Reliability looks at the filter components 24/2/2011 / MJ - P 24 12

13 Design for harmonic compliance Loads If at all possible, measure existing loads or at least voltage distortion Familiar with conditions on site Can be used to calibrate the model Take care of AS/NZS Can be scaled for load changes Many variations / combinations are possible Determine harmonic current emission to be used 24/2/2011 / MJ - P 25 Design for harmonic compliance Network Existing model may be available Many topology variations are possible: fault level, loading, generation, lines connected Documented and agreed topology scenarios Many network variations are possible: voltage deviations, unbalance, frequency deviations Documented and agreed network variations Network model without knowledge of frequency dependency is useless Unbalanced harmonic load flow generally required Wherever possible, calibrate the model from measurements and explain any deviations 24/2/2011 / MJ - P 26 13

14 Design for harmonic compliance Filters Select a filter configuration that is feasible in terms of design and impact on the network Obtain as realistic as possible model for components: resistance of reactors, manufacturing tolerances of components, sensitivity to aging, temperature Document the range of variations in L, C and R General guideline is to keep it as simple as possible: minimum steps, minimum components 24/2/2011 / MJ - P 27 Design for harmonic compliance Compliance test N possible topologies, K network parameters, and M filter parameters that can change N x K x M can easily result in thousands of discrete scenarios Each scenario produces sets of harmonic spectra at multiple busbars Compliance reached with optimal cost solution capital and lifetime 24/2/2011 / MJ - P 28 14

15 Design for harmonic compliance Compliance test Common sense can reduce the number of results Automated analysis process is essential Sensible, compact approach to data representation Box and whisker 24/2/2011 / MJ - P 29 Overview What is a filter Types of harmonic filters What is harmonic compliance Designing for compliance Designing for reliability Other considerations 24/2/2011 / MJ - P 30 15

16 Design for reliability Equipment to be rated to ensure reliable operation Ratings according to manufacturing standards IEC for capacitor units AS/NZS 1028 (or IEC ) for reactors Worst case expected continuous and short time ratings determined from modelling 24/2/2011 / MJ - P 31 Design for reliability IEC for capacitor units AS/NZS 1028 for reactors 24/2/2011 / MJ - P 32 16

17 Overview What is a filter Types of harmonic filters What is harmonic compliance Designing for compliance Designing for reliability Other considerations 24/2/2011 / MJ - P 33 Other considerations Protection and control Acceptable sound emissions Insulation coordination / Impulse withstand Switching transients Seismic and wind loading Standardisation 24/2/2011 / MJ - P 34 17

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